How to make a round tenon on a curved stretcher

[Prashun Patel]

I need to make a curved stretcher for a stool that has one end terminating in a round 5/8" tenon, and another terminating in a 3/4" tenon. I don't have tenon formers this large. The curve prohibits me from turning these on the lathe. How would you do it?

[Malcolm Schweizer]

Make an octagon, then keep knocking off the points, creating more-and-more-sided polygons until you get it round.

[Sean Hughto]

You can rig a jig that would allow you to turn it on the lathe, but it's probably easier to shape them by hand with chisels, rasps and files.

[Steve Voigt]

I do as Malcolm said, with an emphasis on making a perfect square first. That will enable you to make a nice octagon, which will make your chances of a getting a good circle higher.

Here are some pics I took on a project. Lay out and cut the shoulder:

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If you can, use a chisel to split the sides. Much faster and easier with small tenons.

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Pare to make a square:

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Then Octagon and finally a circle.

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[Prashun Patel]

Thanks for the suggestions. I decided to make the stretcher straight. That way I can turn both ends on the lathe. I was hoping for some kind of glue block solution to do a multi axis turning, but I just can't make the geometry work.

[george wilson]

Making a square,then octagon,then 16 sides,etc. is the way the gunsmiths in Williamsburg make round barrels for fowling pieces. Round barrels are much harder to make than octagonals if you don't have a lathe.

I made some special rounding tools for the wheelwright's shop years ago. They are called a Witchel. Google around to find it. Specify they are tools for making round tenons.

[bill howes]

I made some special rounding tools for the wheelwright's shop years ago. They are called a Witchel. Google around to find it. Specify they are tools for making round tenons.[/QUOTE]
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George,
I have heard this called a widget, a rounder and now a witchel. Do you have any insight how this tool came to get its names?
Bill Howes

[Sean Hughto]

I didn't know you hadn't made the curve yet. If that's the case, form the tenons first, and then shape the curve.

[Mike Holbrook]

Yea a chair, stool is close enough!

Lee Valley makes a large reamer for chair making (3/16-1 3/16" diameter, 5 1/2" long, 5/16 hex shank, 12.8 angle, there is a smaller one too). It works well on a hand electric drill, drill press or brace. They also make matching Tapered Tenon Cutters in sizes:3/8,7/16, 1/2,9/16,5/8", also available in the 3 eights sizes as a set. The Tenon cutter works sort of like a pencil sharpener. Schwarz uses them in all his classes and for all his projects. He has been on a staked (tapered mortise & tenon legs) furniture mission for a year or two now. Galbert has a special design, much more expensive, but also uses the LV tools. They actually stay sharp fairly well. You will need to sharpen them though, a diamond paddle works well. These may not be what you need for chair stretches but they make round tenon cutters too. Elia Bizzarri also makes reamers and tenon cutters for legs and stretchers. You can turn a rough round tenon on the lathe and then make it a straight or tapered tenon with the hand tools above.

The tapered tenon in a tapered hole, with a wedge in the top, is what gives legs so much strength. Pressure from above just tightens the joint, you should not even need stretchers. The round tapered & wedged joint using a soft wood for the chair seat and hard for the legs is what keeps the wood from splitting. These fairly simple tools make chair making much easier. I stand on my little saw bench with four staked legs and no stretchers frequently. Good luck!

[Bob Glenn]

If I were doing it, I'd turn the stretcher tenons on a lathe, then steam heat and bend the stretcher.

[Glen Canaday]

Or drill a hole and peg it with a dowel.

[Patrick Chase]

Or drill a hole and peg it with a dowel.

Please. We call them "cylindrical floating tenons" (not to be confused with "ovular pointy-ended floating tenons (http://www.amazon.com/PORTER-CABLE-5554-1000-Assorted-Biscuits/dp/B0000222ZA/ref=sr_1_1?s=hi&ie=UTF8&qid=1461118725&sr=1-1&keywords=joiner+biscuits)")

[Prashun Patel]

Here's how it worked out. Let's call it a puttin-on-the-shoes bench.

This was very (HUMBLY) inspired by a recent visit to Wharton Esherick's studio in Malvern, PA.

I HIGHLY recommend it. He was so unconventional. His sculpted, fluid, yet cleverly functional furniture really speaks to me.

This bench is made from cherry and sycamore scraps.

Drilling the holes by eye was good practice. In the past I've spent so long thinking about jigs and set up, and more and more I'm trying to 'just do it'. I'm fascinated and eluded by the fact that one can saw, drill, and plane perfectly with nothing but your eye and hands. Despite being an engineer at heart, the math side of woodworking has never appealed to me. Ok, back on topic.

This bench was cabinet scraped then sanded from 240 to 600; 2 coats poly/oil.

[Mike Holbrook]

Very interesting, Prashun! beautiful piece of wood. I like the cured lines and how they explore the grain in the wood to great visual effect.

[Jim Koepke]

Very nice work Prashun.

jtk

[Pat Barry]

Nice looking work Prashun. Where was the curved stretcher going to be or were both going to be curved. The straight ones look nice of course but now I am more curious about what your original idea was.

[James Pallas]

Sometimes necessity is the mother of inventions. This is not my idea but it works. Cut the tenon roughly at the angle you need and get it close to size. Find a regular twelve point socket that the ridges are about the right size, tap it on and give it a spin. Newer sockets work better then worn ones. Sometimes you can get a better fit by just tapping it on and leaving the ridges on it.
Jim
PS nice work Prashun. Interesting design too.

[Prashun Patel]

The longer stretcher was originally going to be curved. It would have followed the contour of the rear of the bench.

I have learned a great deal about the elegance of chair and stool design by trying so unsuccessfully to make my own, capricious designs. So much is mandated by the ergonomics and strength, that trying to deviate from some very traditional elements really poses difficulties for construction.

It is illuminating but depressing that it is so hard to create anything new that is also good.

[Lenore Epstein]

That's very pleasing to the eye, Prashun. I just love how you brought out the best features of the wood.